The objective of this research is to extend our knowledge and understanding of the potential of hypoxic cell radiosensitizers for clinical radiotherapy. These studies involve both tumor and normal tissue assays in mice: TCD50 (local tumor control) and skin and leg contraction. The research falls under the following projects: 1. Screening of a limited number of new sensitizers in vivo, using LD50, and TCD50 assays. Growth delay studies will be done when needed. 2. Multifraction studies with misonidazole, using TCD50 and skin and leg contraction assays. The primary goal of these studies is to determine time-dose relationships, and the radiobiological principles underlying them. 3. Multimodality studies with misonidazole and radiation, plus hyperthermia or chemotherapy. Both tumor and normal tissue responses are being investigated.